B.l.t. bolt carrier

ABSTRACT

A bolt assembly is provided for a firearm. The bolt assembly comprises a block adapted to connect to a firearm frame and a bolt carrier adapted to reciprocate within the frame. The bolt assembly comprises a support element between the block and the bolt carrier. The support element is adapted to reciprocate within the frame with respect to the cap and with respect to the bolt carrier. The first and second spaced apart parallel rods are connected to the cap and extending from the cap. The bolt carrier defines a pair of spaced apart bores receiving the rods. A first spring is interposed between the block and the support element, a second spring is received on the first rod, and a third spring is received on the second rod.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation-in-Part of U.S. patent applicationSer. No. 15/718,081 filed on Sep. 28, 2017, entitled “B.L.T. BOLTCARRIER,” which claims the benefit of U.S. Provisional PatentApplication No. 62/400,826 filed on Sep. 28, 2016, entitled “BLT BoltCarrier,” and also claims the benefit of U.S. Provisional PatentApplication No. 62/906,161 filed on Sep. 26, 2019, entitled “B.L.T. BoltCarrier,” which are hereby incorporated by reference in their entiretyfor all that is taught and disclosed therein.

BACKGROUND OF THE INVENTION

Normal AR15 rifles have an extension tube that extends to the rear ofthe upper receiver and contains the recoil spring. Given the length ofthe bolt carrier, the recoil spring needs this length to compress andprovide an adequate range of motion of the bolt carrier. A disadvantageof a standard AR recoil assembly, the travel of the buffer to the rearof the buffer tube causes the weapon to have more felt recoil due tomore mass at the rear of the weapon. While fine for rifles with normalshoulder stocks, the protruding extension tube is a problem for pistolvariants of the AR 15, as well as folding or fully collapsing stocks,which are incompatible with a fixed extension tube.

Accordingly, it is desirable to create a shorter bolt carrier that has arecoil spring capability that operates fully within the limited lengthof an AR-15 upper, with no extension tube. Due to spring resonance of ashorter operating platform, the BCG weight is operating closer to centeraxis, and less recoil is noticed as muzzle flip is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the B.L.T. Bolt Carrier. The assembly includes a boltcarrier 1 that has opposed linear bores. A top-hat shaped center support4 has parallel protruding guide rods 2 that extend into the bores sothat the center support telescopes with respect to the bolt carrier. Thetwo bores associated with the rods are large enough to receivecompression coil springs 16 that bias the center support away from thebolt carrier.

An end cap 5 is threaded 11 to connect to the lower receiver (not shown)on existing threads where a stock might normally be attached, in linewith the center of the barrel bore and bolt carrier. The cap essentiallybecomes the rear wall of the receiver, and the fixed frame of referencethat the bolt reciprocates with respect to. A rear spring (coil,compression) 17 is captured between the center support 4 and the cap.Thus, as the bolt reciprocates, the main springs 16 and rear spring 17both compress, each storing some of the recoil energy for recover forstripping and chambering the next round. The center support 4 floatsbetween the bolt carrier and the cap during recoil cycling, at a middleposition between the two.

If a single rear spring were used (as in a conventional AR-15), it wouldhave to be much longer, and the “end cap” would need to be lengthened tobecome an extension tube. This is partly due to the need to absorbrecoil energy, and partly due to the length of the fully collapsedspring when the coils are stacked against each other, a conditionnormally to be avoided. It is not possible to extend the rear springforward into or around the bolt carrier because of the needed structureand functions of the bolt carrier. However, the main spring that residesin part within the bolt carrier bore provides this added springcapability without lengthening the rear spring undesirably. The threesprings are essentially end to end, and the entire rear spring remainsto the rear of the entire front spring in all conditions. These areserially connected with the center support gripped or pinched betweenthem, and each spring has a size and shape based on the space it has towork within the B.L.T. BCG.

In this exploded view, the image shows the rear view of the main springzero footprint pocket (6), the guide rods (2) that are attached to thecenter support (4). The end cap is the end of the B.L.T. BCG that housesthe solid height of the rear spring.

FIG. 2 shows the installed length with a frontal view looking to theright side to the rear. The B.L.T. utilizes a milspec bolt. The bore ismilspec diameter (15).

FIG. 3 shows the installed length with the right side of the B.L.T. BCG.The guide rod bore hole goes through the entire BCG. The end cap showsthe threads with a 1 3/16″-16 tpi pitch is how the end cap attaches tothe lower receiver.

FIG. 4 shows the view when the B.L.T. carrier is in collapsed positionfrom being fired. In this position, the retention guide rod is showingthrough the ejection port cutout. The center support recesses internallyinto the end cap fully compressed.

FIG. 5 shows a top view image looking down on the installed length,ready to fire. This spring technology has zero footprint solid height.The main springs recess internally in the carrier. The rear springrecesses into the end cap.

The rear spring 17 presses on the rear surface of the flange of thecenter support 4, and the main springs press on the front surface of theflange, guided by the rods.

FIG. 6 shows the B.L.T. Bolt Carrier. The assembly includes a boltcarrier 1 that has opposed linear bores. A top-hat shaped center support4 has parallel protruding guide rods 2, 3 that extend into the bores sothat the center support telescopes with respect to the bolt carrier. Theretention guide rod 3 has a flared tip that prevents the center supportassembly from falling out of the bolt carrier. The bore associated withrod 2 is large enough to receive a compression coil spring 16 (notshown) that biases the center support away from the bolt carrier.

An end cap 5 is threaded 11 to connect to the lower receiver (not shown)on existing threads where a stock might normally be attached, in linewith the center of the barrel bore and bolt carrier. The cap essentiallybecomes the rear wall of the receiver, and the fixed frame of referencethat the bolt reciprocates with respect to. A rear spring (coil,compression) 17 is captured between the center support 4 and the cap.Thus, as the bolt reciprocates, the main spring 16 and rear spring 17both compress, each storing some of the recoil energy for recovery forstripping and chambering the next round. The center support 4 floatsbetween the bolt carrier and the cap during recoil cycling, at a middleposition between the two.

If a single rear spring were used (as in a conventional AR-15) it wouldhave to be much longer, and the “end cap” would need to be lengthened tobecome an extension tube. This is partly due to the need to absorbrecoil energy, and partly due to the length of the fully collapsedspring when the coils are stacked against each other, a conditionnormally to be avoided. It is not possible to extend the rear springforward into or around the bolt carrier because of the needed structureand functions of the bolt carrier. However, the main spring that residesin part within the bolt carrier bore provides this added springcapability without lengthening the rear spring undesirably. The twosprings are essentially end to end, and entire rear spring remains tothe rear of the entire front spring in all conditions. These areserially connected with the center support gripped or pinched betweenthem, and each spring has a size and shape based on the space it has towork within.

In this extended position/installed length is a see through image thatshows internal view of the main spring zero footprint pocket (6), thesmooth guide rod (2) that is attached to the center support (4) by thethreaded end (8), the retention guide rod (3) and the flared tip (7)that is inserted through the carrier from the front to the centersupport where it is threaded into the center support (4), now thecarrier (1), main spring (16), guide rods and center support connectedin operational order. The end cap is the end of the B.L.T. BCG thathouses the solid height of the rear spring.

FIG. 7 shows installed length showing a frontal view looking to theright side to the rear. The B.L.T. utilizes a milspec bolt. The bore ismilspec diameter (15), utilizes milspec dust cover cutout (12).

FIG. 8 shows installed length showing the right side of the B.L.T. BCG,the guide rod bore hole goes through the milspec ejection port cutout.The end cap shows the threads with a 1 3/16″-16 tpi pitch is how the endcap attaches to the lower receiver.

FIG. 9 shows the B.L.T. carrier is in collapsed position from beingfired. In this position the retention guide rod is showing through theejection port cutout. The center support recesses internally into theend cap.

FIG. 10 shows a cutaway view from the bottom looking up in the collapsedposition when in recoil from being fired.

FIG. 11 shows a cutaway view from the top looking down in the extendedinstall length ready to be fired.

FIG. 12 shows a top view image looking down on the installed length,ready to fire. This spring technology with zero footprint solid height.The main spring on the left side shows how the spring recessesinternally in the carrier. The rear spring recesses into the end cap.

The rear spring 17 presses on the rear surface of the flange of thecenter support 4, and the main spring presses on the front surface ofthe flange, guided by the rod 2.

FIG. 13 shows the same view as FIG. 12, but in the fully compressedcondition in full recoil. The center support 4 ensures that if a firstone of the springs is fully compressed so that the coils touch eachother, then the other spring will have some accommodation to limit this“crash” before it can have a harmful effect.

FIG. 14 is fully compressed no springs.

FIG. 15 is a frontal view looking from the left side to the rear.

LIST OF THE PARTS

-   1. B.L.T. (Bufferless technology) Bolt Carrier-   2. Guide Rod Smooth-   3. Guide Rod Retention-   4. Center support-   5. End cap-   6. Main spring “zero footprint” pocket-   7. Flared end of retention guide rod-   8. Threaded guide rod ends-   9. Standard Cam cutou-   10. Standard gas key cutout-   11. End cap threads (standard buffer threads)-   12. Standard dust cover cutout-   13. Standard Gas stake bolt holes-   14. Gas hole-   15. Milspec B.C.G. bore hole-   16. Main spring-   17. Rear spring

DESCRIPTION OF ALTERNATIVE EMBODIMENT(S)

FIG. 16 shows an alternative embodiment of the B.L.T. Bolt Carrier. Somecallouts are duplicated from other figures and should be clear withrespect to the figure and embodiment being discussed. The assemblyincludes a bolt carrier 1 that has opposed linear bores. A two-piecetop-hat shaped center support 3 & 4 has a rear bump stop 7 and internalbump stops 8 with parallel protruding guide rods 2 that extend into thebores so that the center support telescopes with respect to the boltcarrier. The bores associated with rod 2 is large enough to receive acompression coil spring 16 (not shown) that biases the center supportaway from the bolt carrier. In addition, a recoil catch 14 attaches intothe upper receiver (not shown) to prevent overtravel and stopping recoilassembly in correct position.

An end cap 105 is threaded 11 to connect to the lower receiver (notshown) on existing threads where a buffer tube might normally beattached, in line with the center of the barrel bore and bolt carrier.The cap essentially becomes the rear wall of the receiver and the fixedframe of reference that the bolt reciprocates with respect to. A rearspring (coil, compression not shown) 17 is captured between the centersupport 3 & 4 and the end cap 5. Thus, as the bolt reciprocates, the twomain springs 16 and rear spring 17 both compress, each storing some ofthe recoil energy for recovery for stripping and chambering the nextround. The center support 3 & 4 floats between the bolt carrier and theend cap during recoil cycling, at a middle position between the two.

Additionally, a slide weight 13 secured to the bolt carrier via carriergas key 10 or other means of attachment if the BCG has an integrated gaskey (not shown) spring-loaded to absorb energy in both directions oftravel, slowing the opening time when a round is fired, and securingproper lockup into battery.

If a single rear spring were used (as in a conventional AR-15), it wouldhave to be much longer, and the “end cap” would need to be lengthened tobecome an extension tube. This is partly due to the need to absorbrecoil energy, and partly due to the length of the fully collapsedspring when the coils are stacked against each other, a conditionnormally to be avoided. It is not possible to extend the rear springforward in to or around the bolt carrier because of the needed structureand functions of the bolt carrier. However, the main springs thatresides in part within the bolt carrier bore provides this added springcapability without lengthening the rear spring undesirably. The two mainsprings in parallel are essentially stacked on the rear spring, andentire rear spring remains to the rear of the entire front springs inall conditions. These are serially connected with the center supportgripped or pinched between them, and each spring has a size and shapebased on the space it has to work within.

In this extended position/installed length is an image that shows a topside view of the main spring zero footprint pocket (6) that can extendthrough the slide weight (13), the smooth guide rod (2) that is attachedto the center support (3 & 4), that is inserted through the slide weight(13) and the carrier (1). The end cap is the end of the B.L.T. BCG thathouses the solid height of the rear spring. To secure stocks, braces orany type of attachments, an adapter (20 & 21) secured to the back oflower receiver (not shown) is attached by the end cap (5) securingadapter mounting plate (21) to the lower receiver, and rail adapter (20)attaching to adapter mounting plate.

FIG. 17 shows the installed length with a frontal view looking from theright side to the rear. The B.L.T. utilizes a milspec bolt (15). Thebore is milspec diameter and utilizes a milspec carrier gas key (10).Internal center support bump stops (8) are made of polymers andpolyurethane

FIG. 18 shows the installed length with a frontal right side to the rearview of the B.L.T BCG with installed main springs (16) and rear spring(17).

FIG. 19 shows when the B.L.T. carrier (1) is in the collapsed positionfrom being fired, the center support recesses internally into the endcap (5).

FIG. 20 is an exploded right side view, and all components listed areshown.

Firing pin plunger (12) has a spring attached (18) that is secured bythe milspec retainer pin (not shown), keeping pressure outward on thestandard milspec firing pin (20) away from the primer of the ammunition.

FIG. 21 is an exploded view of the right side showing all componentsminus springs. The end cap shows that threads with a 1 3/16″-tpi pitchis how the end cap attached to the lower receiver.

FIG. 22 is an exploded frontal view looking from the right side to therear, and all components listed are shown.

FIG. 23 is an exploded rearward view looking from the right side to thefront, and shows all components listed minus springs.

FIG. 24 is a right side view of the B.L.T. bolt carrier (1) with slideweight (13) fully collapsed.

FIG. 25 is a right side top frontal view of the B.L.T. bolt carrier (1)with slide weight (13) fully collapsed showing the linear path (23) theslide weight travels from open to collapsed. The slide weight is securedby the carrier gas key or other means if the carrier has an integratedgas key or a modified gas system.

FIG. 26 is a right side view of the B.L.T. bolt carrier (1) with slideweight (13) in the open position. In this position, the spring pressure(19) keeps the slide weight away from the bolt carrier between0.15″-0.25″ depending on the application (caliber, barrel length,suppressed or un-suppressed). When a round is fired, the bolt carriermoves rearward and the slide weight spring compresses, closing the gapbetween the slide weight and bolt carrier. When the bolt carrier impactsthe slide weight, the slide weight slows the carrier. When the boltcarrier (1) is returning to battery, stripping the next round from themagazine (not shown), the spring pressure (19) returns the slide weightto the open position. When the bolt carrier (1) and bolt (15) lock intobattery, the slide weight follows forward from the inertia (compressingthe spring for the slide weight) to the closed position impacting thebolt carrier (1), thus giving a dead blow effect to the bolt carrierthereby ensuring proper lockup and reducing bolt bounce.

FIG. 27 is a right side top frontal view of the B.L.T. bolt carrier (1)with slide weight (113) at the open, resting position. This image showsthe linear path (23) of how the slide weight travels from open toclosed.

FIG. 28 is a right side cross-section view of the installed length,minus springs.

FIG. 29 is a right side cross-section view of the installed length,showing springs. Length is conserved by telescoping the springs withinthe length of the bolt carrier (101), so that they bear near the frontof the bolt carrier.

FIG. 30 is a right side cross-section view fully collapsed in the firedposition minus springs.

FIG. 31 is a right side cross-section view fully collapsed in the firedposition with springs.

LIST OF THE PARTS

-   1. B.L.T. (bufferless technology) Bolt Carrier-   2. Guide Rod-   3. Center support front-   4. Center support rear-   5. End cap-   6. Main spring “zero footprint” pocket-   7. Rear center support bump stop-   8. Internal center support bump stops-   9. Milspec cam pin-   10. Milspec carrier gas key-   11. End cap threads (milspec buffer tower threads)-   12. Firing pin plunger-   13. Slide weight-   14. Recoil assembly catch-   15. Milspec bolt-   16. Main springs-   17. Rear spring-   18. Spring, firing pin plunger-   19. Spring, slide weight-   20. Milspec firing pin-   21. Adapter interface-   22. Mount, adapter interface-   23. Linear path, slide weight

The claimed invention is:
 1. A bolt assembly for a firearm comprising: ablock adapted to connect to a firearm frame; a bolt carrier adapted toreciprocate within the frame; a support element between the block andthe bolt carrier; the support element adapted to reciprocate within theframe with respect to the cap and with respect to the bolt carrier; arod connected to the cap and extending from the cap; the bolt carrierdefining a bore receiving the rod; a first spring interposed between theblock and the support element; and a second spring received on the rod.